I had thought that this spark was period-4. Using a known trick, I isolated the spark further. This allowed a small interaction with the block deletion in the p20 and p28 ships, resulting in nontrivial p40 and p56 ships:

The reason for all of these c/4 orthogonal results is that I have been working on my update to jslife, and have added a c/4 orthogonal extended collection. Looking back through old technology gave me some new ideas. I am now done updating all of the collections of moving objects in jslife except c/3 orthogonal.

Also, thanks to Dave Greene's Life Lexicon update, I noticed this c/4 orthogonal ship (by Nicolay Beluchenko) that should have been in the small ships collection:

Sokwe wrote:Please let me know If you find any errors, omissions, or inconsistencies.

Thanks a lot for compiling this collection, it's great to have.

I don't know if this counts as an omission in the strict sense, but one thing I'd love to see is information on who first found which ship, when, and so on, in the same manner as in Dean Hickerson's oscillator stamp collection.

I was just looking for Eppstein's glider glider 16485 (that's 70P2H1V0.1 on Pentadecathlon); found it right away, too, in velocity-c2/c2-extended/c2-0002.rle (again, thanks to everyone!), but as there's no meta-information about any of the ships I'm still in the dark about who first discovered it.

If you speak, your speech must be better than your silence would have been. — Arabian proverb

Apple Bottom wrote:I don't know if this counts as an omission in the strict sense, but one thing I'd love to see is information on who first found which ship, when, and so on, in the same manner as in Dean Hickerson's oscillator stamp collection.

I was just looking for Eppstein's glider glider 16485 (that's 70P2H1V0.1 on Pentadecathlon); found it right away, too, in velocity-c2/c2-extended/c2-0002.rle (again, thanks to everyone!), but as there's no meta-information about any of the ships I'm still in the dark about who first discovered it.

Many (perhaps most) patterns in the collection do have that information. That happens to be one of the exceptions. The main reason the information isn't included is that it's just too much work to track down. I spent nearly as much time finding credits for old patterns as I did adding new patterns.

To answer your specific curiosity, 70P2H1V0.1 was found by Hartmut Holzwart sometime in the two weeks preceding 3 July 1992. It was found with the restriction that all on cells have at most 6 on neighbors and all off cells have at most 5 on neighbors. This allows it to work in many different rules, which is probably why David Eppstein included it in his database.

I found the information for this spaceship by first looking at David Bell's article, "Spaceships in Conway's Life (Part 2)" (available from his website). It mentions that Hartmut started searching for p2 ships in June of 1992, and that this specific ship had been found "recently". I then looked at some old email archives to find the specific message in which the ship was posted. Unfortunately, the email archive is not available for public release.

Sokwe wrote:I found the information for this spaceship by first looking at David Bell's article, "Spaceships in Conway's Life (Part 2)" (available from his website). It mentions that Hartmut started searching for p2 ships in June of 1992, and that this specific ship had been found "recently". I then looked at some old email archives to find the specific message in which the ship was posted. Unfortunately, the email archive is not available for public release.

Excellent, thanks for the detective work!

I'm curious, too -- how come the archives aren't available? Wasn't this a public mailing list?

If you speak, your speech must be better than your silence would have been. — Arabian proverb

The mailing list was not public. As I understand it, the reason the archives aren't made public is that not everyone on the list has given explicit permission. Since the archives date back to April 1992, it might be hard to even get in contact with some of the members. Dave Greene has more details (sorry Dave).

These archives are basically only useful for finding historical information. Even then, most of the interesting historical information has ended up in publicly-available pattern collections and articles.

C/9 is negative at w8 for a, v, and u symmetries. I have not done w8 g yet, but w8 v took over one and a half months, so it will be a while. I am running 3c/10 w9 a and v right now, which will take a while.

Thanks for the new results. I had been neglecting the status table for a while, but I have now updated it.

Also, notice that any asymmetric ships will show up in a gutter-symmetric search of the same width, so it usually isn't necessary to run the asymmetric search. Of course, if the gutter-symmetric search finds a ship that is not composed of two asymmetric ships, then you will need to run the asymmetric search.

Goldtiger997 wrote:Edit: a very minor result, no 5c/11 ships up to w9.

This result was also reported earlier by A for Awesome. I have completed the width 10 searches for this speed with zfind-s. There were no results. The gutter search took about 15 hours and the odd and even symmetric searches took just under a day each. Here are some partials: